If it were me, I would stick with the conventional tank style water heaters because they CAN supply all the hot water you need, whereas that's still a big question with tankless heaters.

In fact, in a house in the town I grew up in, the builder (who was a plumber by trade) put a ball valve in the basement separating the kitchen and one bathroom from the laundry room and the other bathroom. He installed two 60 gallon hot water tanks and had one to supply each side of the house. He did that because he had three daughters and they were always fighting over the one bathroom in their old house.

I thought that was actually a smart idea because the cost of a water heater isn't that much, AND the two water heaters don't have to be identical. They can be totally different and his system would still work fine. And, the best part of it is, if you ever have to shut one water heater down (to replace the annode rod, for example), then you can open that ball valve and have the heater that's still operational supply water to the whole house until the work is done.

If I were building a house, that's probably the route I'd go.